The internal courtyard of the Caseggiato dei Triclini on the main street of Ostia

Well, I’m almost done (fingers crossed) with the current chapter covering internal spaces in Ostia and the aural architecture of certain spaces. I touched on doorways in a previous post on common shops found along the streets of Ostia. I am now working through more complex buildings than the one room shop.

Another common architectural layout for various types of buildings is that of an internal courtyard. These buildings, referred to as insulae, are usually large, multistory and multifunctional, both commercial and residential. The courtyard was usually a communal space, but in some cases only accessible from the ground floor. Again, because of the common occurrence of courtyards and the various functions of the buildings, the courtyards are another prime space for questioning the way acoustics can be utilised in various functional settings.

While wrestling with ways of analysing an interior but open space, I came across a study of street noise and urban courtyards. It was an interesting look at the low frequency noise from streets being heard inside courtyards in urban settings. One of the aspects that stood out to me was the way the arrangement of the courtyard functioned as a resonator for certain frequencies of noise produced on the street. Simply put low frequency noises, which have higher wavelengths than high frequencies, would carry over the buildings and enter the courtyard. It seemed that the lowest frequencies could be heard at almost the same level in the courtyard as the street. Resonant frequencies, those frequencies that would resonant in the courtyard, produce increases in the sound level in the courtyard, while the sound propagation in street decreased. The study suggests that urban courtyards are not quite retreats from the noises of urban streets but in fact can be just as loud, even louder at certain frequencies.

Returning to Ostia, this suggests that the internal courtyards of certain buildings would have a similar reaction to street noise. Low frequency traffic noise would not happen in Ostia but other low frequency noise and resonant frequencies would still fill the courtyard. In certain cases, doors and walls could block some of the sound waves, although this would not stop all noises (remember that the low frequency noise would fill the urban courtyards even when there was no doorway from the street to the courtyard in the model). Here again, we get yet another occasion where places thought to be quite or removed from activity still react and are filled with noise. Some of the internal courtyards in Ostia now seem to be even more active spaces than I initially thought.